Antiproteinase 3 (PR3) Antibodies

Antineutrophil cytoplasmic antibodies (ANCA) are a group of antibodies directed against cytoplasm antigens of neutrophilic granulocytes and monocytes. ANCA examinations are considered basic tests in immunological laboratories. The determination of ANCA is of great importance, in particular in the case of suspected acute vasculitis of small vessels, with severe pulmonary impairment or renal failure, but also in some non-vasculitis clinical syndromes such as inflammatory bowel diseases, e.g. ulcerative colitis. The most common target antigens of ANCA-associated vasculitis are proteinase 3 or myeloperoxidase. Antibodies against proteinase 3 (PR3) are referred to as c-ANCA fluorescent subtype, namely cytoplasmic antibodies (granular cytoplasmic fluorescence). PR3 is a neutral serine proteinase 3, also known as Wegener's autoantigen. Antibodies against PR3 are a highly specific marker in diagnosing Wegener's granulomatosis.